The Resolved Questions page  only mentions Public Domain in connection with Doug Lea's concurrent library.
Public Domain is not specifically listed under any category.
A concrete example is the code at  which says:
Written by Brian Goetz and Tim Peierls with assistance from members of
JCP JSR-166 Expert Group and released to the public domain, as explained at
The CC document  linked above includes the words "or Public Domain Certification".
I think it would be helpful if  were updated to clarify whether the inclusion of  "Creative Commons Copyright-Only Dedication" means that all works "released to the public domain" are covered, or only works that follow the example above and reference .